OP0264 COST-UTILITY OF A PROGRESSIVE SPACING OF TOCILIZUMAB OR ABATACEPT IN PATIENTS WITH RHEUMATOID ARTHRITIS IN SUSTAINED REMISSION: A MEDICO-ECONOMIC ANALYSIS OF THE TOLEDO TRIAL
Authors: J. Kedra, B. Granger, L. EL Houari, F. Tubach, B. Fautrel
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Biologic Disease Modifying Anti-Rheumatic Drugs (bDMARDs) progressive tapering is a real opportunity in people living with rheumatoid arthritis (RA) having achieved remission both from the patient and the Society perspectives. The ToLEDo (Towards the Lowest Efficacious Dose) trial aimed to assess a disease activity-driven progressive tapering strategy of tocilizumab (TCZ) or abatacept (ABA) compared to their maintenance at full dose in RA patients in sustained remission. Non-inferiority (NI) was not demonstrated in terms of disease activity (primary endpoint) nor relapses, major relapses, radiographic progression (secondary endpoints) [1]. <h3>Objectives</h3> The aim of this secondary analysis was to assess the cost-utility of the spacing strategy (S-arm) in the ToLEDo trial compared to full dose maintenance (M-arm). <h3>Methods</h3> The ToLEDo trial is a multicenter 2-year NI randomized open-label controlled trial, which enrolled 228 patients (113 in the S-arm and 115 in the M-arm). A cost-utility analysis was conducted on the per protocol population. In each arm, health benefits were estimated every 6 months by Short Form Health Survey (SF-6D) and EuroQoL (EQ-5D)-derived utility measurements. Cost elicitation integrated health resource use including bDMARD costs (direct cost) as well as productivity loss (indirect cost) using the friction cost method. The incremental cost-utility ratios (ICUR) were calculated by dividing the difference of costs between S-arm and M-arm by the difference of utilities between the 2 arms. 95% confidence interval (95%CI) were calculated by bootstrap (20,000 iterations). The incremental net benefit (INB) was calculated for willingness to pay (WTP) values ranging from 0 to 150,000€. The analyses were replicated using SF-6D (primary analysis) or EQ-5D, and in ABA and TCZ subgroups. Acceptability analyses as well as stochastic sensitivity analyses (simulating costs and utilities using MCMC algorithms) were also performed. <h3>Results</h3> Overall, 178 patients were included (82 in S-arm, 96 in M-arm) in the per protocol analysis. At the end of the follow-up in the S-arm, 15.0% of patients discontinued their biologic, 48.7% spaced the injections, and 36.3% remained at the standard dose. The difference in terms of two-years utility gains between S-arm and M-arm was 0.004 (95%CI -0.012, 0.021) with SF-6D. The difference of total costs between S-arm and M-arm was -4,275 € (95%CI -5,955 to -2,542). The estimated ICUR of the spacing strategy over the maintenance at full dose was €932,003 saved per QALY (95% CI -7,534,788 to 6,720,372) with SF-6D. The INB was 4,734.6€ for a WTP of 100,000€. With a willingness to accept of 0 €/QALY lost, the probability to be cost-effective for the spacing strategy was 70.6% (<b><i>Figure 1</i></b>). The results were consistent when using EQ-5D-derived utilities, in ABA and TCZ subgroups, as well as in the stochastic sensitivity analyses (<b><i>Table 1</i></b>). <h3>Conclusion</h3> Although the ToLEDo trial did not demonstrate non-inferiority, the tested disease activity-driven tapering strategy was not associated with health loss in terms of utilities and incurred for substantial cost savings, making this strategy potentially dominant. <h3>Reference</h3> [1]Kedra J, Dieudé P, Marotte H et al. Towards the Lowest Efficacious Dose (ToLEDo): Results of a Multicenter Non-Inferiority Randomized Open-Label Controlled Trial Assessing Tocilizumab or Abatacept Injection Spacing in Rheumatoid Arthritis Patients in Remission [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). <h3>Acknowledgements</h3> The authors acknowledge the investigators and pharmacists who participated in the ToLEDo trial, the Pharmacoepidemiology Center of the Assistance Publique-Hôpitaux de Paris (Centre de Pharmaco-Epidémiologie [CEPHEPI]) for the supervision of the project and monitoring and management of the data, and the CRI-IMIDIATE network. <h3>Disclosure of Interests</h3> Joanna KEDRA: None declared, Benjamin Granger Consultant of: BMS, Lina EL HOUARI: None declared, Florence Tubach Consultant of: UCB, MSD, Lundbeck, Bruno Fautrel Consultant of: AbbVie, Amgen, Biogen, BMS, Celltrion, Fresenius Kabi, Galapagos, Gilead, Janssen, Lilly, Medac, MSD, Mylan, NORDIC Pharma, Novartis, Pfizer, Roche, Sandoz, Sanofi-Genzyme, SOBI, UCB, Grant/research support from: AbbVie, Lilly, MSD and Pfizer.